Productive and breeding qualities of black-and-white cows of different lines

The main task of dairy cattle breeding remains to increase the productivity of animals by breeding the most valuable breeds, genotypes and lines of cattle. In this way, it is relevant to study the influence of economically useful traits of cows of the 1st calving of different lines on their milk production. The research base was formed on the basis of the information and analytical system «Selex - Dairy cattle» for 2,269 cows of the 1st calving of the black-and-white breed in one of the leading agricultural enterprises of the Vologda region - the Breeding farm «Aurora». As a result of the research, it was found that cows of the 1st calving belonging to four lines (Vis Back Ideal 1013415, Reflection Sovering 198998, Pubs Governor 882933 and Montvik Chieftain 95679) had noticeable differences in the main economically useful characteristics. Thus, the highest productivity indicators (8465 kg) were in cows of the 1st calving Pabs Governer 882933, significantly the lowest (7504 kg) - in cows of the 1st calving Montvik Chieftain 95679. At the same time, it should be noted that cows of all lines had milk yield above the breed standard by an average of 2-2.5 times. In terms of fat content, the superiority of cows of the 1st calving of the Pabs Governor 882933 line over their peers from other groups and the average herd was 0.07-0.13%, in terms of milk fat yield by an average of 7-17%. The yield of milk fat in cows of the Vis Back Ideal 1013415 and Montvik Chieftain 95679 lines was lower than the average for the herd by 2 and 27 kg, respectively. The largest amount of milk protein by weight was obtained from animals of the Pabs Governer line 882933 - 280 kg. The highest mass fraction of protein in milk was found in the lowest-yielding cows of the 1st calving of the Montvik Chieftain line 95679 (3.80%), and the lowest - in high- yielding peers of the Pabs Governor line 882933 (3.13%), the difference was 0.67%, i.e. there is a negative relationship between milk yield and the mass fraction of protein. The highest coefficient of milk production (1532 kg) was observed in cows of the 1st calving of the Pabs Governor 882933 line. The difference with other groups and with the average herd was 3.5- 14%. Among the four lines of cows of the 1st calving of the black-and-white breed with year-round stable maintenance, the animals of the lines Vis Back Ideal 1013415, Reflection Sovering 198998 and Pabst Governer 882933 were distinguished by high economic efficiency. The economic efficiency of using cows of these lines in total in the Breeding Farm - Collective Farm «Aurora» is 377754.6 thousand rubles or 16.9 thousand rubles per animal. Thus, in order to obtain high milk yields with good technological properties, it is advisable to use animals of the Vis Back Ideal 1013415, Reflection Sovering 198998 and Pabst Governer 882933 lines in the farm, which combine a high level of milk productivity and fat content.